Image Letter

Polymorphic Vessels—Think About Seborrheic Keratosis

Author Affiliation(s)

Case Presentation

A 57-year old man with known multiple atypical nevi presented for his regular yearly follow-up visit. He had no history of personal or familial melanoma. During the visit, we observed a roundish, well-demarcated, nodular lesion with a diameter of 8 mm on his right flank. A shiny surface, some scales at the periphery and clinically visible vessels were observed. The lesion was firm on palpation. On dermoscopy, the lesion presented a polymorphic vascular pattern (linear- irregular, glomerular, and hairpin vessels), blue-reddish lacunae randomly distributed over the lesion as well as some hemorrhagic crusts ( Figure 1, A and B ).

Figure 1 .

(A) Clinical image showing a roundish, well-demarcated red nodule with a maximum diameter of 8 mm. Additionally, a shiny surface, some peripheral scales, and different types of vessels are observable. (B) On dermoscopy, a polymorphic vascular pattern composed of linear-irregular, glomerular, and hairpin vessels is evident. Moreover, blue-reddish lacunae and hemorrhagic crusts are seen.

The nodule was excised, and histopathology showed an irritated seborrheic keratosis with reactive atypia.

Teaching Point

Seborrheic keratoses, especially irritated lesions, present in a huge morphological variety clinically and dermoscopically. These lesions can exhibit features suggestive of amelanotic melanoma, Merkel cell carcinoma (eg, polymorphic vessels), or basal cell carcinoma and require histological examination [ 1 , 2 ] .


  1. The many faces of seborrheic keratosis Carrera C. Actas Dermosifiliogr.2019;110(5):338. CrossRef
  2. Dermoscopic clues for diagnosing melanomas that resemble seborrheic keratosis Carrera C, Segura S, Aguilera P, et al. JAMA Dermatol.2017;153(6):544-551. CrossRef PubMed

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